When will the yam be harvested? What are the main diseases and insect pests? Attached prevention and control measures

Chinese yam, also known as Dioscorea zingiberensis, Huai Shan, yam, sweet potato and so on, is a kind of plant for both medicine and food, and it is often planted in our country. When will the yam be harvested? What are the main diseases and insect pests? What are the prevention and control measures?

When will the yam be harvested?

Chinese yam was harvested from the period of Frosts Descent, when all the stems and leaves withered, and the harvest period of open-air planting was longer around October-November. But the planting in the greenhouse is different, and it is usually harvested around June 20.

Second, what are the main diseases and insect pests of yam?

1. Anthrax

Anthracnose mainly harmed the leaves and stems of Chinese yam. At the initial stage of the disease, the leaves appeared yellow-white small disease spots, which gradually spread into irregular disease spots. The disease spots joined with the leaves in brown, and black spots appeared in the center.

two。 Brown spot disease

Brown spot, also known as leaf blight, mainly harms the leaves of Chinese yam. Yellow-white spots appear in the lower half of the leaves at the onset of the disease, and in the later stage, the spots spread and turn brown, and there are black particles in the center. When these particles break, it will lead to leaf perforation and often wither and die when the disease is serious.

3. Root rot disease

Root rot mainly harms the rhizome of Chinese yam, the disease is not easy to find in the root system, the plant appears small brown spots at the base of the rattan stem at the beginning of the disease, with the passage of time, the disease spot gradually expands and becomes dark brown, and the center of the disease spot is sunken. When the disease is serious, there are brown mildew filaments in the disease spot, and the rhizome atrophies and decays, which eventually leads to plant death.

4. Grubs, red spiders

Grubs mainly harm the root system of Chinese yam, often gnawing on the root block of Chinese yam, making it grow slowly and affecting quality, while red spiders mainly harm leaves, which often cluster on the back of yam leaves and absorb the sap of leaves, resulting in loss of water and yellow and fall of leaves, resulting in plant atrophy and premature senescence.

Third, what are the main pest control measures of Chinese yam?

(1) Agricultural prevention and control

Disease-resistant varieties, rotation, soil preparation, field cleaning, fertilization, irrigation and other measures were adopted to avoid or reduce the occurrence of yam diseases and insect pests.

1. The selection of disease-resistant varieties is an effective method to control diseases and insect pests of yam. Such as: the selection of Taigumao yam can resist stem rot. When cultivating disease-resistant varieties, the varieties should be rotated every 2 ~ 3 years, and attention should be paid to the purification and rejuvenation of the varieties.

two。 Rotation can reduce or avoid the harm of stem rot and root-knot nematode of Chinese yam. Rotation with corn, wheat, radish, watermelon and other uninfected crops at least once a year; in the old areas where yam is cultivated all the year round, it should be rotated once a year; in conditional areas, water-early rotation can be implemented, and the control effect is better.

3. Soil preparation can directly eliminate pathogens overwintering in the soil. Selecting high dry, low humidity, fertile and loose sandy loam for soil preparation in autumn, the diseased remains left on the surface can be turned into the soil, accelerate the decomposition and decay of the diseased bodies, and lose the vitality of some pathogens after freezing in winter and drying in spring.

4. Fertilizing and irrigating yam are fertilizer-loving crops, and rotten organic fertilizer must be applied during soil preparation. Generally, the application of phosphorus and potassium fertilizer is beneficial to the formation of mechanical tissue of Chinese yam and enhance the ability of resistance to pathogenic bacteria. Excessive application of nitrogen fertilizer is easy to cause overgrowth of plants, tender stem and leaf tissue, and easy to get Chinese yam anthracnose. The principle of watering is "do not water early". When watering with clean water, you must water thoroughly, there can be no stagnant water in the field, and drainage should be done in time during the rainy season to avoid root rot.

5. The field is clean and the weeds in the field should be eliminated manually. The timely removal of the leaves and stems of the diseased yam can reduce the re-infection of pathogens. When the yam is harvested, the diseased remains, weeds and rotten stems left on the ground should be burned or taken out of the field for deep burial to reduce overwintering pathogens.

(2) Chemical control

Including chemical protection and chemotherapy. Chemical protection is to spray fungicides before the disease of yam to prevent the invasion of pathogens. Chemotherapy is to spray medicine after the disease is infected by yam to restore the health of the plant or prevent the disease from spreading. There are mainly three kinds of prevention and control of yam diseases and insect pests: seed potato treatment, soil disinfection and plant spraying. It is worth noting that one month before the harvest of yam, do not use medicine, in order to prevent pollution to tubers and affect the quality of yam. Chemical control should use pesticides with high efficiency, low residue, low toxicity and safety, and cooperate with other control methods.

1. Chinese yam anthracnose harms stems and leaves, causing stem withering and falling leaves. Control method: the seed potato was soaked in 1RU / 1RV 150 solution for 10 minutes. Spray chlorothalonil with 600 times of chlorothalonil for the first time and spray it for the second time 10 days later. From July to August, it was found that 65% Dysen zinc wettable powder 500 times, 50% bacilli special wettable powder 800 times, 50% methyl topiramate 700 times 800 times, spray 2 times 4 times according to the severity of the disease, and spray alternately. Every time the interval is 8 to 10 days, the spray solution should be replenished after the rain.

Yam can be listed as soon as it is harvested, and the storage of tubers is mainly heat preservation and antifreezing, with a suitable temperature of 2-4 ℃ and a relative humidity of 80-85%. Can be stacked, buried or cellar and so on.